1. Field of the Embodiments
The embodiments are generally directed to luminescent solar concentrator systems and more particularly to combinations of materials and layer architectures for improving power output.
2. Summary of Existing Art
The ability to generate useful power from the sun forms the basis of an entire industry—the solar industry. The applications for such power are too numerous to list. Depending on the application, there are many design trade-offs that must be made between economics and efficiency. For example, design characteristics will vary significantly between large, stationary solar arrays that are permanently installed in the desert and portable solar arrays for relatively quick set-up, e.g., by soldiers, hikers or others on the move who might require a smaller power output from the solar collection system.
In order to reduce the number and/or size of photovoltaic cells (PVCs) in a solar collection system, and thus reduce expense, imaging solar concentrators have been developed to collect sunlight over a large area and direct it onto a small area of PVCs. Such concentrators must track the sun across the sky and require precise alignment with the underlying PVCs in order to maximize collection. Such imaging solar concentrators are unable to make use of diffuse solar radiation.
An alternative to the imaging solar concentrator is a non-imaging concentrator. A particular implementation of a non-imaging concentrator is a luminescent solar concentrator (LSCs). In prior art implementations, an LSC is comprised of transparent plates, e.g., glass or polymer, containing luminophores, e.g., organic dyes, that absorb solar spectrum. Resulting from the absorption, the luminescence from the luminophore is down shifted to longer wavelength which is in the absorption spectrum of the PVC which has been optimized for the luminophore. The concentration results from light pipe trapping of luminescence.
Descriptions of existing implementations of LSC collection systems are found in the following references which are incorporated herein by reference in their entirety: A. M. Hermann, “Luminescent solar concentrators—A review,” Solar Energy, vol. 29, no. 4, pp. 323-329, 1982; P. S. Friedman and C. R. Parent, “Luminescent solar concentrator development,” SERI/STR-211-3149, 1980; V. Wittwer, W. Stahl, and A. Goetzberger, “Fluorescent planar concentrators,” Sol. Energy Mater., vol. 11, no. 3, pp. 187-197, 1984; P. S. Friedman, “Progress on the development of luminescent solar concentrators,” in SPIERole of Electro-Optics in Photovoltaic Energy Conversion, 1980, pp. 98-104; K. Barnham et al., “Quantum-dot concentrator and thermodynamic model for the global redshift,” Appl. Phys. Lett., vol. 76, no. 9, pp. 1197-1199, 2000; M. H. V. Werts, et al., “Fluorescein and eosin as sensitizing chromophores in near-infrared luminescent ytterbium(III), neodymium(III) and erbium(III) chelates,” Chem. Phys. Lett., vol. 276, no. 3/4, pp. 196-201, 1997; M. J. Currie et al., “High-Efficiency Organic Solar Concentrators for Photovoltaics”, Science 321 (2008), p. 226; L. H. Sloof, et al., “A luminescent solar concentrator with 7.1% efficiency”, phys. stat. sol. (RRL), 2(6), pp. 257-259 (2008); M. Kennedy, et al, “Improving the optical efficiency and concentration of a single-plate quantum dot solar concentrator using near infra-red emitting quantum dots”, Solar Energy 83 (2009); S. J. Gallagher, B. Norton, P. C. Eames, “Quantum dot solar concentrators: Electrical conversion efficiencies and comparative concentrating factors of fabricated devices”, Solar Energy, 81, (2007); Zimmerman, Paul A., et al, “High Index 193 nm immersion lithography: the beginning or the end of the road.” Optical Microlithography XXII. Ed. Harry J. Levinson & Mircea V. Dusa, San Jose, Calif., USA SPIR 2009, 727420-11. While these existing LSC collection systems theoretically should provide for systems having increased efficiency due to use of both direct and diffuse solar radiation, actual implementations have not heretofore proven out the theory.
There is a need for a portable solar collection system which is of a size and flexibility that allows for relatively easy set-up and also produces enough power so as to be useful for the user's purposes.